A symposium on developmental reproductive biology and sexual differentiation will be held in conjunction with the 12th annual meeting of the Society for the Study of Reproduction at the University of Laval, Quebec, Canada. Three scientists will discuss the current "states of the art" with respect to the immunogenetics, endocrine-genetics and epithelial-stromal interactions in sexual differentiation, while another three will consider sex refersal in lower forms, the role of hormones in brain development, and in the psychosexual differentiation of the human. Together, these six presentations will evaluate the fundamental aspects of developmental reproductive biology and also consider how comparable are the processes of the differentiation of the peripheral reproductive organs and the brain. The proceedings of the symposium will be published in the February, 1980 issue of the Biology of Reproduction.